Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On Tue, Apr 14, 2015 at 03:01:00PM +0200, Wiebe Cazemier wrote: - Original Message - From: Wiebe Cazemier wi...@halfgaar.net To: Michael Niedermayer michae...@gmx.at Cc: FFmpeg development discussions and patches ffmpeg-devel@ffmpeg.org, madshi mad...@gmail.com Sent: Monday, 6 April, 2015 7:25:16 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default has someone contacted justin ? I did now. Sorry, I was still kind of spacing out on what to do next... As of yet no response. Do we take the other decision making route? If you belive that a listed maintainer in the MAINTAINERs file no longer wants to / no longer is maintaining the code he is listed for in FFmpeg. Then yes please post a patch that corrects the MAINTAINERs file with a CC to anyone whos status is changed and explanation in the commit message [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB During times of universal deceit, telling the truth becomes a revolutionary act. -- George Orwell signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On 14 April 2015 at 14:01, Wiebe Cazemier wi...@halfgaar.net wrote: - Original Message - From: Wiebe Cazemier wi...@halfgaar.net To: Michael Niedermayer michae...@gmx.at Cc: FFmpeg development discussions and patches ffmpeg-devel@ffmpeg.org, madshi mad...@gmail.com Sent: Monday, 6 April, 2015 7:25:16 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default has someone contacted justin ? I did now. Sorry, I was still kind of spacing out on what to do next... As of yet no response. Do we take the other decision making route? No because votes in FFmpeg are historically a bad idea. Kieran ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
- Original Message - From: Wiebe Cazemier wi...@halfgaar.net To: Michael Niedermayer michae...@gmx.at Cc: FFmpeg development discussions and patches ffmpeg-devel@ffmpeg.org, madshi mad...@gmail.com Sent: Monday, 6 April, 2015 7:25:16 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default has someone contacted justin ? I did now. Sorry, I was still kind of spacing out on what to do next... As of yet no response. Do we take the other decision making route? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
- Original Message - From: Kieran Kunhya kier...@obe.tv To: Wiebe Cazemier wi...@halfgaar.net Sent: Monday, 30 March, 2015 3:43:42 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default It's in the spec as an *option*, to cater to those who have bad sound systems. If ffmpeg already applies DRC, and software using ffmpeg doesn't set 'drc_scale', it's no longer an option, it becomes mandatory. That's the issue. It is not an option and I quote ETSI 102 366: Therefore, the AC-3 decoder shall, by default, implement the compression characteristic indicated by the dynrng values in the data stream. AC-3 decoders may optionally allow listener control over the use of the dynrng values, so that the listener may select full or partial dynamic range reproduction. If an application doesn't want to expose drc settings then that's their problem. FFmpeg does the right thing and lets you turn it off if you wish. Kieran (can you reply-all, so that your reply goes to the list?) If you say it's not an option, that's putting it harder than the spec say. Dolby engineers never meant AC3 audio to be played compressed everywhere, and that's what we're seeing happening. Also, I feel that the word 'decoder' in your quote is written in a time where it had a different context and that quote has to be interpreted that way. Open source software libraries weren't available at that point, and a decoder was a piece of hardware, or a chip embedded in something. Sure, you don't have to allow the user to control it when you embed an AC3 decoder in your budget TV so ATSC demanding that you do would be silly here, but all high end receivers I know, do allow you to set the option. Now that we do have a library that people can use, an honest mistake to forget to implement it turns into something that they probably didn't intend. As proven by the Kodi developer denying that they applied DRC. I think we have to consider user experience, and it's great when they can control it, but we're getting the situation where everybody gets it (yet only for AC3), whether they want to or not. That automatically crosses off Kodi and VLC (for example) for use in high quality sound reproduction. And the bad thing is, they may not even know it... ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
- Original Message - From: Kieran Kunhya kier...@obe.tv To: Wiebe Cazemier wi...@halfgaar.net Sent: Monday, 30 March, 2015 10:47:49 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default It is not an option and I quote ETSI 102 366: Therefore, the AC-3 decoder shall, by default, implement the compression characteristic indicated by the dynrng values in the data stream. AC-3 decoders may optionally allow listener control over the use of the dynrng values, so that the listener may select full or partial dynamic range reproduction. If an application doesn't want to expose drc settings then that's their problem. FFmpeg does the right thing and lets you turn it off if you wish. Kieran (can you reply-all, so that your reply goes to the list?) If you say it's not an option, that's putting it harder than the spec say. Dolby engineers never meant AC3 audio to be played compressed everywhere, and that's what we're seeing happening. Also, I feel that the word 'decoder' in your quote is written in a time where it had a different context and that quote has to be interpreted that way. Open source software libraries weren't available at that point, and a decoder was a piece of hardware, or a chip embedded in something. Sure, you don't have to allow the user to control it when you embed an AC3 decoder in your budget TV so ATSC demanding that you do would be silly here, but all high end receivers I know, do allow you to set the option. Now that we do have a library that people can use, an honest mistake to forget to implement it turns into something that they probably didn't intend. As proven by the Kodi developer denying that they applied DRC. I think we have to consider user experience, and it's great when they can control it, but we're getting the situation where everybody gets it (yet only for AC3), whether they want to or not. That automatically crosses off Kodi and VLC (for example) for use in high quality sound reproduction. And the bad thing is, they may not even know it... It's the complete opposite - most people are watching on laptop speakers without the dynamic range you have in your setup. FFmpeg lets you turn it off and it's the fault of the player for not exposing that. What about those people playing AAC, which is the majority currently. In any case, I made my point. How do we proceed? I have no idea who is in charge of what, and how the decision making process goes in ffmpeg development. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
From: Kieran Kunhya kier...@obe.tv To: Wiebe Cazemier wi...@halfgaar.net Sent: Monday, 30 March, 2015 3:43:42 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default It is not an option and I quote ETSI 102 366: Therefore, the AC-3 decoder shall, by default, implement the compression characteristic indicated by the dynrng values in the data stream. AC-3 decoders may optionally allow listener control over the use of the dynrng values, so that the listener may select full or partial dynamic range reproduction. Let me ask you: The DVD and Blu-Ray specs require that a DVD/Blu-Ray player not allow the user to skip forced video parts (like anti-piracy clips or sometimes even trailers). So since the spec says so, we should make sure that all open source media players also follow the spec to the letter and not allow users to skip forced video clips? Is that truly your opinion? And if the spec asks you to shoot yourself in the foot, you do that, too? How about using some common sense: What should have priority? The best user experience? Or following some stupid instructions in a spec? As I said before, the only situation where the default value matters (and we're only asking to change the default value, not to remove the ability to apply dynamic range compression altogether) is when the software using ffmpeg is not aware that there is such a thing as the drc_scale option. In this situation of course you can blame the software. But the end result is that the end user experience will suffer, because ffmpeg will output subpar quality in that situation. What good is that for anybody? What do you think would happen if we started a vote like the following: 1) Should ffmpeg output reduced (range compressed) audio quality by default, because the spec says so? 2) Should ffmpeg output full (range) quality by default, unless the software asks ffmpeg to do otherwise? How many users or devs would vote for 1) or 2)? And you didn't answer the question I asked before: Why would only AC3 have range compression on by default? Why not any other codec? What is the sense in that?? Are you saying that laptop speakers are not able to play full range AC3 tracks, but that they *are* able to play full range TrueHD tracks? If you truly believe that range compression should be on by default, then you should be consistent about it, and ask for range compression to be enabled by default for all other audio decoders, too. We're intelligent beings, we don't have to blindly follow everything some stupid spec says. Best regards, Mathias. 2015-03-30 9:38 GMT+02:00 Wiebe Cazemier wi...@halfgaar.net: - Original Message - From: Kieran Kunhya kier...@obe.tv To: Wiebe Cazemier wi...@halfgaar.net Sent: Monday, 30 March, 2015 3:43:42 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default It's in the spec as an *option*, to cater to those who have bad sound systems. If ffmpeg already applies DRC, and software using ffmpeg doesn't set 'drc_scale', it's no longer an option, it becomes mandatory. That's the issue. It is not an option and I quote ETSI 102 366: Therefore, the AC-3 decoder shall, by default, implement the compression characteristic indicated by the dynrng values in the data stream. AC-3 decoders may optionally allow listener control over the use of the dynrng values, so that the listener may select full or partial dynamic range reproduction. If an application doesn't want to expose drc settings then that's their problem. FFmpeg does the right thing and lets you turn it off if you wish. Kieran (can you reply-all, so that your reply goes to the list?) If you say it's not an option, that's putting it harder than the spec say. Dolby engineers never meant AC3 audio to be played compressed everywhere, and that's what we're seeing happening. Also, I feel that the word 'decoder' in your quote is written in a time where it had a different context and that quote has to be interpreted that way. Open source software libraries weren't available at that point, and a decoder was a piece of hardware, or a chip embedded in something. Sure, you don't have to allow the user to control it when you embed an AC3 decoder in your budget TV so ATSC demanding that you do would be silly here, but all high end receivers I know, do allow you to set the option. Now that we do have a library that people can use, an honest mistake to forget to implement it turns into something that they probably didn't intend. As proven by the Kodi developer denying that they applied DRC. I think we have to consider user experience, and it's great when they can control it, but we're getting the situation where everybody gets it (yet only for AC3), whether they want to or not. That automatically crosses off Kodi and VLC (for example) for use in high quality sound reproduction
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
And you didn't answer the question I asked before: Why would only AC3 have range compression on by default? Why not any other codec? What is the sense in that?? Are you saying that laptop speakers are not able to play full range AC3 tracks, but that they *are* able to play full range TrueHD tracks? If you truly believe that range compression should be on by default, then you should be consistent about it, and ask for range compression to be enabled by default for all other audio decoders, too. We're intelligent beings, we don't have to blindly follow everything some stupid spec says. We should have DRC enabled in AAC and other codecs if it's considered a normative part of the spec. Kieran ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On Mon, Mar 30, 2015 at 11:28:29AM +0100, Kieran Kunhya wrote: On 30 March 2015 at 11:24, madshi mad...@gmail.com wrote: 2015-03-30 12:10 GMT+02:00 Kieran Kunhya kier...@obe.tv: We should have DRC enabled in AAC and other codecs if it's considered a normative part of the spec. So basically you do what the spec says regardless of whether it makes sense or not? Yes, for FFmpeg, this is not true. ISO mpeg4 specified one way to do QPEL, but the reference implementation did it the other way. Our decoder tries hard to figure out which of the 2 was used on the encoder side and matches it when decoding. IIRC the mpeg4 spec was changed to match the implementation at some point then as well Some mpeg4 encoders do the edge handling for MC wrong, we detect them and match it in the decoder. That way the user sees a nice video instead of one with minor or not so minor artifacts. We clearly violate a normative part of the spec by displaying these videos without artifacts we also detect some ancient buggy version of x264 and decode that different from what the spec would require to match what the encoder did, the above examples are of course bug workarounds but then there is no spec that says output video with a modified gamma compared to the encoder input unless the user override that or does one ? [...] and we let power users change things from the API - I don't see why that's so hard. Kieran ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Concerning the gods, I have no means of knowing whether they exist or not or of what sort they may be, because of the obscurity of the subject, and the brevity of human life -- Protagoras signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On Sun, Mar 29, 2015 at 07:01:08PM +0200, Wiebe Cazemier wrote:
Signed-off-by: Wiebe Cazemier wi...@halfgaar.net
---
Changelog | 1 +
doc/decoders.texi | 2 +-
libavcodec/ac3dec_fixed.c | 2 +-
libavcodec/ac3dec_float.c | 2 +-
libavutil/version.h | 2 +-
5 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/Changelog b/Changelog
index 109a1b8..0bd9875 100644
--- a/Changelog
+++ b/Changelog
@@ -11,6 +11,7 @@ version next:
- nvenc H265 encoder
- Detelecine filter
- Intel QSV-accelerated H.264 encoding
+- Dolby Digital dynamic range compression disabled by default
version 2.6:
diff --git a/doc/decoders.texi b/doc/decoders.texi
index 01fca9f..ba78a31 100644
--- a/doc/decoders.texi
+++ b/doc/decoders.texi
@@ -72,7 +72,7 @@ from the AC-3 stream. This factor is applied exponentially.
There are 3 notable scale factor ranges:
@table @option
@item drc_scale == 0
-DRC disabled. Produces full range audio.
+DRC disabled. Produces full range audio. Default value.
@item 0 drc_scale = 1
DRC enabled. Applies a fraction of the stream DRC value.
Audio reproduction is between full range and full compression.
diff --git a/libavcodec/ac3dec_fixed.c b/libavcodec/ac3dec_fixed.c
index b4beee6..e3c8ce8 100644
--- a/libavcodec/ac3dec_fixed.c
+++ b/libavcodec/ac3dec_fixed.c
@@ -168,7 +168,7 @@ static void ac3_downmix_c_fixed16(int16_t **samples,
int16_t (*matrix)[2],
#include ac3dec.c
static const AVOption options[] = {
-{ drc_scale, percentage of dynamic range compression to apply,
OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 6.0, PAR },
+{ drc_scale, percentage of dynamic range compression to apply,
OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 0.0}, 0.0, 6.0, PAR },
{ heavy_compr, heavy dynamic range compression enabled,
OFFSET(heavy_compression), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, PAR },
{ NULL},
it might make sense to add a -1 value to drc_scale with the
meaining do what the spec says
this way if 2 decoders in the future support the drc_scale option
it would be possible for a user to set them to use the defaults
from their specs even if these defaults differ
but this should be a seperate patch of course, so arguable that isnt
a comment about this patch
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Republics decline into democracies and democracies degenerate into
despotisms. -- Aristotle
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Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
Michael Niedermayer wrote: Apologies for the slightly out of place response. I've only just subscribed after reading the rest of this thread via the archive. I'm with KieranK the exception should be full range for those that can stand it. Maybe I am not best placed to comment as I mixdown to 2ch, but while people here argue that full range is better quality, I would agree a bit, but unfortunately many movies are mixed in such a way that in order to hear the dialogue the loud bits become way way too loud for comfort. The argument that DTS/AAC/TrueHD decs don't do it IMHO is invalid as in the latter two cases at least this is only due to incomplete (and from my pov sometimes therefore unusable) implementations. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On Mon, Mar 30, 2015 at 11:37:10AM +0200, Wiebe Cazemier wrote: - Original Message - From: Kieran Kunhya kier...@obe.tv To: Wiebe Cazemier wi...@halfgaar.net Sent: Monday, 30 March, 2015 10:47:49 AM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default It is not an option and I quote ETSI 102 366: Therefore, the AC-3 decoder shall, by default, implement the compression characteristic indicated by the dynrng values in the data stream. AC-3 decoders may optionally allow listener control over the use of the dynrng values, so that the listener may select full or partial dynamic range reproduction. If an application doesn't want to expose drc settings then that's their problem. FFmpeg does the right thing and lets you turn it off if you wish. Kieran (can you reply-all, so that your reply goes to the list?) If you say it's not an option, that's putting it harder than the spec say. Dolby engineers never meant AC3 audio to be played compressed everywhere, and that's what we're seeing happening. Also, I feel that the word 'decoder' in your quote is written in a time where it had a different context and that quote has to be interpreted that way. Open source software libraries weren't available at that point, and a decoder was a piece of hardware, or a chip embedded in something. Sure, you don't have to allow the user to control it when you embed an AC3 decoder in your budget TV so ATSC demanding that you do would be silly here, but all high end receivers I know, do allow you to set the option. Now that we do have a library that people can use, an honest mistake to forget to implement it turns into something that they probably didn't intend. As proven by the Kodi developer denying that they applied DRC. I think we have to consider user experience, and it's great when they can control it, but we're getting the situation where everybody gets it (yet only for AC3), whether they want to or not. That automatically crosses off Kodi and VLC (for example) for use in high quality sound reproduction. And the bad thing is, they may not even know it... It's the complete opposite - most people are watching on laptop speakers without the dynamic range you have in your setup. FFmpeg lets you turn it off and it's the fault of the player for not exposing that. What about those people playing AAC, which is the majority currently. In any case, I made my point. How do we proceed? I have no idea who is in charge of what, and how the decision making process goes in ffmpeg development. Generally decissions are made based on consensus or absence of objections. If that doesnt work there should be a maintainer for the specific part of the code. Iam not sure AC3 in FFmpeg does have a maintainer, justin is listed in MAINTAINERs but iam not sure if justin still (wants) to maintain ac3 in FFmpeg. so considering that kierank and andy seem to object to this patch someone should 1. ask justin if he is still MAINTAINING AC3 in FFmpeg 2a. if yes, ask him what to do 2b. if no send a patch to update the MAINTAINERs file and if noone else wants to maintain AC3 the decission would proably fall onto me, unless theres something resembling a consensus by then also independant of this, its probably a good idea if we make our users more aware of the drc_scale option. A news entry and or some mention in the next release notes is probably a good idea patches in that direction are welcome Thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Concerning the gods, I have no means of knowing whether they exist or not or of what sort they may be, because of the obscurity of the subject, and the brevity of human life -- Protagoras signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
2015-03-30 12:10 GMT+02:00 Kieran Kunhya kier...@obe.tv: We should have DRC enabled in AAC and other codecs if it's considered a normative part of the spec. So basically you do what the spec says regardless of whether it makes sense or not? Best regards, Mathias. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On 30 March 2015 at 11:24, madshi mad...@gmail.com wrote: 2015-03-30 12:10 GMT+02:00 Kieran Kunhya kier...@obe.tv: We should have DRC enabled in AAC and other codecs if it's considered a normative part of the spec. So basically you do what the spec says regardless of whether it makes sense or not? Yes, and we let power users change things from the API - I don't see why that's so hard. Kieran ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
2015-03-30 12:28 GMT+02:00 Kieran Kunhya kier...@obe.tv: Yes, and we let power users change things from the API - I don't see why that's so hard. It's not hard. The only problem is that there are many many applications out there using ffmpeg, and many (most?) of them are not aware of drc_scale. So they decode AC3 with subpar quality. And there's nothing the *end user* can do about it. Most end users are not aware of the problem, so they get subpar quality without even knowing it. Sure, you can blame the applications for not setting drc_scale. I blame ffmpeg instead, for outputting subpar quality *by default*. Best regards, Mathias. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
Le decadi 10 germinal, an CCXXIII, madshi a écrit : What do you think would happen if we started a vote like the following: 1) Should ffmpeg output reduced (range compressed) audio quality by default, because the spec says so? 2) Should ffmpeg output full (range) quality by default, unless the software asks ffmpeg to do otherwise? How many users or devs would vote for 1) or 2)? Kieran will answer you the spec is right even if it tells you that 2+2=5. ;-) My answer is: profile, don't speculate. Q: the user has quality audio equipment that can play full range K: the user knows that there is an option D: quantified damage to the sound (subjective impression translated to an approximate value) d1: quantified damage of playing compressed range on quality equipment d2: quantified damage of playing full range on poor equipment d3: quantified damage of having to set an option E(D) = P(K)×d3 + P(¬K∧Q)×d1 if compression is the default E(D) = P(K)×d3 + P(¬K∧¬Q)×d2 is compression is disabled by default. So basically, you need to provide convincing estimates for the ratio between P(¬K∧Q) and P(¬K∧¬Q) and the one between d1 and d2. Regards, -- Nicolas George signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
2015-03-29 20:06 GMT+02:00 Kieran Kunhya kier...@obe.tv: On 29 March 2015 at 18:01, Wiebe Cazemier wi...@halfgaar.net wrote: Signed-off-by: Wiebe Cazemier wi...@halfgaar.net Why can't you just set this in your application? Not everyone is listening on a full setup where they can hear the dynamic range. There are 2 possible situations: 1) Either the software using ffmpeg is aware of the drc_scale option. If that is the case, the software is likely to set the option to the desired value. So in this case it doesn't matter which value we set the default to. 2) Or the software using ffmpeg is not aware of the drc_scale option. In this case currently ffmpeg defaults to applying range compression, which severely damages audio quality. Which is a very bad idea. So basically this patch tells ffmpeg to produce full decoding quality, unless it's asked to do otherwise. Which is the only sane setup, IMHO. If you think that range compression should be turned on by default, then we should patch all other decoders to also do that by default. Why only AC3? Makes no sense. Best regards, Mathias. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
On 29 March 2015 at 18:01, Wiebe Cazemier wi...@halfgaar.net wrote: Signed-off-by: Wiebe Cazemier wi...@halfgaar.net Why can't you just set this in your application? Not everyone is listening on a full setup where they can hear the dynamic range. Kieran ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default
- Original Message - From: Kieran Kunhya kier...@obe.tv To: Wiebe Cazemier wi...@halfgaar.net Cc: Kieran Kunhya kier...@obe.tv Sent: Sunday, 29 March, 2015 10:03:05 PM Subject: Re: [FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default There was another thread about it (discussed with Michael Niedermayer, among others). In short, developers don't seem to know about or don't implement the feature. Kodi developers denied that it applied DRC on AC3, not knowing that ffmpeg did it. This meant that DRC couldn't be turned off. VLC also lacks the option, but does apply it. If applications want DRC, they should set the drc_scale option. Having ffmpeg do it creates mystery behavior. DRC is in the spec, if you want to violate the spec, then turn it off yourself. How? It's in the spec as an *option*, to cater to those who have bad sound systems. If ffmpeg already applies DRC, and software using ffmpeg doesn't set 'drc_scale', it's no longer an option, it becomes mandatory. That's the issue. Madshi's explanation is spot on. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
